Wooden window units having protective coverings

ABSTRACT

A two-part laminated wooden sash having a groove along its inner face for receiving peripheral portions of a window pane and sealant material in the groove is provided. The external wooden sash part is provided with a dual plastic extrusion having a first portion forming a generally U-shaped sheath of semi-rigid material for receiving the first part prior to final assembly of the wooden unit. The second portion of the extrusion includes a flexible lip along the edge of the sheath for sealing against the window pane. In another form hereof, dual and triple panes of glass are employed to provide insulating panels with spacers between the panes, or a single pane of glass.

United States Patent Eisenberg 5] June 6, 1972 [54] WOODEN WINDOW UNITS HAVING 1,525,260 2 1925 Anderson ..52 302 PROTECTIVE COVERINGS 8,725 4/1936 .52/616 3,345,791 10/1967 ....52/6l6 [72] Inventor: Morris M. Elsenberg, Ste. Genevieve, Mo. 3,478,473 1 H1969 52/309 [73 Assigneez Bihbest Corporation, Sta Genevieve, Mu 3,553,913 l/l97l Elsenberg ..52/6 l 6 X [22] Filed: May I, 1970 i FOREIGN PATENTS OR APPLICATIONS [2 Appl. No.: 33,809 1,227,913 3/1960 France ..52/309 Related U.S. Application Data Primary Examiner-Alfred C. Perham [63] Continuation-impart of Ser. No. 856,630, Sept. 10, AHOmey Le Blane & Shut 1969, Pat. No. 3,553,9l3, which is a continuation-inpart of Ser. No, 687,748, Dec. 4, 1967, abandoned.

[57] ABSTRACT A two-part laminated wooden sash having a groove along its inner face for receiving peripheral portions of a window pane and sealant material in the groove is provided. The external wooden sash part is provided with a dual plastic extrusion having a first portion forming a generally U-shaped sheath of semi-rigid material for receiving the first part prior to final assembly of the wooden unit. The second portion of the extrusion includes a flexible lip along the edge of the sheath for sealing against the window pane. In another form hereof, dual and triple panes of glass are employed to provide insulating panels with spacers between the panes, or a single pane of glass.

6 Claims, 10 Drawing Figures PATENTEnJun 6|972 3.667. 179

sum 1 or 2 INVENTOR MORRIS M, EiSENBERG ATTORNEYS PATENTEDJun s 1912 SHEET 2 OF 2 INVENTOR MORRIS M EISENBERG BY 4 ATTORNEYS WOODEN WINDOW UNITS HAVING PROTECTIVE COVERINGS This application is a continuation-in-part of application Serial No. 856,630 filed Sept. 10, 1969, now U.S. Pat. No. 3,553,913, dated Jan. 12, 1971, which application Serial No. 856,630 is, in turn, a continuation-in-part of application Ser. No. 687,748 filed Dec. 4, 1967, now abandoned.

The present invention relates to wooden window units having a protective outer covering and particularly to single, double and triple pane wooden window units having a durable plastic covering about the Weather exposed wood portions of the sash.

Conventional window units, particularly for home use, but limited thereto, usually comprise a plurality of wooden sash members arranged to form a window sash and having a groove along their inner faces for receiving peripheral portions of the window pane, or glass panel in the case of dual or triple pane insulating window units. One side of the wooden sash is normally exposed to environmental conditions and therefore requires periodic attention. For example, old and peeling paint must be periodically removed and a fresh coat or two of paint applied if the wooden sash is to be maintained. This also increases the labor involved as the window pane must be subsequently scraped clean after the paint dries. In addition, conventional window typically require recaulking if leaks and further deterioration of the wood are to be prevented. The opposite portions of the wooden sash member, i.e., those portions exposed internally of the building or home, are not exposed to environmental conditions and typically do not require the periodic maintenance to the extent that the outer exposed portions of the sash members require such maintenance and can usually be repainted or stained over intervals two or three thimes as long as the externally exposed wooden sash portions require painting and/or maintenance. On many occasions, it is also often desirable to retain the natural wood finish of the wooden sash on its inside face to preserve its aesthetic features.

Protective coverings for wood window sash members are known and have been utilized in the past. In United States Letters Patent No. 3,082,490 there is disclosed a window unit having a three-part construction with inner and outer members secured to a central member. The inner and outer members are provided with a plastic covering whereby both the internally and externally exposed surfaces are protected. Further, in that construction, the glass pane is secured to the three-part sash by means of a rather complex arrangement of angle members. The cost and labor involved in providing a window of this type is accordingly quite high.

ln another form of window unit heretofore proposed and constructed, there is provided a unitary sash member received within a substantially rectangular envelope of plastic material wherein the plastic material completely encases the wooden sash member. A groove is formed along the inner face of the envelope toprovide a dove-tail connection with a second plastic member which bears against the window pane to retain it in the sash. It has been found that the dove-tail connection is not satisfactory and that the second plastic member is, on occasion, free to pop out of the window unit allowing moisture to enter. Additionally, with this construction, internally exposed portions of the sash member are unnecessarily covered whereby the aesthetic features of a stained or painted window on the inside portion thereof cannot be obtained.

The present invention provides an improved window unit having a protective covering on one side thereof, which eliminates and minimizes the above-discussed shortcomings and disadvantages of prior window units having protective coverings and provides various features and advantages in comparison with such known window units. Particularly, the present invention provides a window unit including a plurality of sash members forming the outer frame of the window unit. The sash members have a continuous groove formed along their inner faces for receiving a glass pane or a glass panel in the case of dual or triple pane window insulating units. Each of the sash members comprises a two part construction. The first part includes an elongated wooden strip forming the wooden portion of the sash exposed externally to one side of the window unit while the other or second part comprises a portion of the wooden sash exposed internally of the window unit. The second part has a recess formed along its inner face and, when the first and second parts are secured one to the other, the side wall and bottom portions of the recessas well as the inner face portion of the first part form the peripheral groove for receiving the glass pane or panels.

Each first wooden sash part is inset along its inner face along opposite edges thereof, and is provided with a plastic sheath forming the protective outer surface for the wooden sash. Particularly, the sheath is comprised of a dual extrusion of plastic material having a first, generally semi-rigid, U- shaped portion enclosing the major portion of the first wooden part and a second generally flexible lip or bead-like portion projecting from the sheath for engagement in sealing relation against the window pane as the externally exposed pane of a single, dual or triple pane window unit. The generally U- shaped sheath has a pair of inwardly extending flanges which are received within the inset portions of the first part whereby the first part can be readily slipped within the sheath. When the first and second parts are subsequently finally secured one to the other, the flange along the outer edge of the window unit is retained within the inset portion of the first part between the first and second parts while the flange extending along the inner face of the sash member is retained between the first part and the glass pane or panel.

It is desirable to obtain circulation of air between the plastic coating and the first part as well as to permit expansion of the wooden first part and the plastic coating at different rates whereby cracking of the plastic sheath can be prevented. To this end, the plastic sheath is, during assembly of the window unit, freely slideable along the first wooden part and constrained in final assembly by the mitered seals at the corners of the window unit and, in part, by the loose clamping action by the two wooden parts about the outer flange of the sheath.

In constructing the present window unit, the first parts of the sash members are inserted within the respective sheaths. Where insulating window units are fabricated, the glass panels are formed separately by disposing spacers along the peripheral edges of the panels and applying a sealant about the spacers and the peripheries of the panel to form a hermetic seal. The panel or pane is then located within the recessed portions of the seconds parts of the sash which have been previously secured one to the other to form the window frame. Additional sealant is provided between the margin of the panel and the recess and the first sash parts are then secured to the second sash partsas by gluing one to the other with the marginal portions of the glass pane or panel being thus disposed within the groove formed by the first and second sash parts.

The plastic covering is extruded such that the soft flexible bead bears in sealing relation against the window pane. Weep holes are provided along the lower sash member in communication with the sealant in the groove to drain any condensation or moisture which may form along the juncture of the first and second sash parts and the sealant material as well as between the plastic coating and the first sash part.

Accordingly, it is a primary object of the present invention to provide an improved wooden window unit having a protective covering along the exposed portion of the wooden sash, i.e., the surface exposed to environmental weather conditions.

It is another object of the present invention to provide a novel improved window unit having a unitary composite protective plastic covering along the environmentally exposed outer surface of its wooden sash. It is a related object to provide such window unit wherein the protective coating has a sealing lip for preventing leakage into the glazing groove.

lt is still another object of the present invention to provide an improved wooden window unit having a protective coating along its externally exposed wooden sash portions for use with single, double, and triple pane insulating glass panels.

. vention will become more apparent upon reference to the following specification, appended claims and drawings wherein:

' FIG. 1 is a cross-sectional view of a multiple pane wooden window unit having a protective covering constructed in accordance with the present invention, and having portions broken away for ease of illustration;

FIG. 2 is an exploded fragmentary perspective view of an insulating glass panel employed with a form of the window assembly hereof;

FIG. 3 is a fragmentary cross-sectional view of the glass panel and illustrating the clamp maintaining the panel in assembled relation;

FIG. 4 is a fragmentary perspective view of the glass panel illustrated in conjunction with a tool for applying sealant along the edge portion thereof;

FIG. 5 is a cross-sectional view of the glass panel illustrating the application of a sealant between it and a part of the wooden sash;

FIG. 6 is a cross-sectional view of the glass panel and the sash part illustrated in FIG. 5 after the sealant has been applied and another sash part, the sash parts being illustrated in exploded juxtaposition prior to final assembly thereof;

FIG. 6A is a fragmentary cross-sectional view of the edge portion of the protective covering illustrating its dual extruded construction; I

FIG. .7 is a fragmentary perspective view of a corner of the window unit illustrating theseal at the mitered comer of the protective covering;

; FIG. 8 is a fragmentary cross-sectional view of a wooden window unit and a glass panel thereforillustrating another form of the present invention; and

FIG. 9 is a fragmentary perspective view of the inside face of a part of the wooden sash illustrating the weep holes.

Referring now to the drawings and particularly to FIG. 1, there is shown a three-pane insulating glass panel, generally indicated at' l0,-disposed within a wooden sash, generally indicated at 12, of a window unit W. The three-pane insulating glass panel 10 comprises three sheets ofglass 14 maintained in spaced relation one from the other by spacers 16 which define, with next adjacent pairs of glass panes 14, a pair of dead air spaces indicated at 18. Spacers 16 are made of sheet metal, preferably aluminum, pressed to form a substantially hollow, generally T-shaped, cross section, as particularly illustrated in FIG. 3, with the longitudinally extending oppositeedges of the sheet metal spacers l6 lying in opposed relationto form slits as at 20 inwardly of the periphery of glass panel 10. As illustrated in FIGS. 1 and 3, the lateral walls 22 forming base portions of the T-shaped cross section are inset or indented to form a space between the lateral edges of glass panes 14 and spacers 16 which space opens outwardly of panel 10 for reasons as will presently become clear.

In a standard rectangular window unit, four spacers 16 are arranged between each of the next adjacent pairs of glass panes 14 along the laterally facing peripheral edges thereof, each spacer 16 forming right angles with the adjoining spacers at opposite ends thereof. As seen in FIG. 2, the ends of adjoining spacers 16 are cut at right angles and right angle members 24, preferably zinc castings, may be inserted into the ends of the adjoining spacers to forma rectangular spacer framework when assembling the glass panel as will be described hereinafter. Spacers l6 are-hollow and provide longitudinally extending receptacles encompassing the dead air spaces 18 between adjacent glass panes for receiving a suitable desiccant 26 having moisture absorbing properties, such as silica gel. The spaces or slits 20 between the opposed edges of the aluminum sheets forming spacers 16 provide suitable openings between the desiccant and dead air spaces 18 whereby the latter can be maintained in a dehydrated condition.

The wooden window sash l2 peripherally encompasses glass insulating panel 10 and comprises, in the illustrated form, four rectangularly disposed composite wooden frame members. It will be understood that reference to a rectangularly shaped window unit is made herein for convenience of description only and that other window shapes may be constructed. Any suitable standard method of joining the composite wooden sash members of the frame 12, one to the' other, at their ends may be employed, such as mortised and tenoned or slotted and pinned construction, not shown. Each of the composite wooden frame members is formed of a twopart construction for reasons as will presently become clear, and includes first and second parts 30 and 32 respectively. The first part 30 comprises an elongated wooden strip, generally rectangular in cross section, having along its inner periphery a reversed curved edge portion 34 and forms the wooden portion of the sash which is exposed externally to one side of the window unit. That is to say, in final construction and use, the part 30 is that wooden portion of the sash which would normally be exposed to external environmental conditions. The second wooden sash part 32 of each frame member comprises the portion of the wooden sash exposed internally of the window unit, as for example interiorly within a room of a house, building or the like, and is of generally rectangular cross section with a groove 36 formed along its inner edge along one side thereof. In final securement, it will be seen that, when parts 30 and 32 are secured one to the other, groove 36 forms, with the inner face of sash part 30, a glazing groove 38 for receiving the marginal portions of glass panel 10.

It is a particular feature of the present invention that the window unit is provided with a protective covering along its externally or exteriorly exposed wooden sash portions. To this end, prior to securingthe first and second parts one to the other and before final assembly of the window, there is provided a protective sheath 40 about the exteriorly exposed faces of sash part 30, whereby the outer surface of the wooden sash is fully protected from environmental conditions. Preferably, the sheath 40 is formed of a plastic material inert to weathering, such as polyvinyl chloride. It is a further par- 1 ticular feature hereof, for reasons as will become apparent, that the sheath 40 comprises a dual extrusion of plastic materials, having a first, generally semi-rigid, U-shaped portion 42 disposed about the major portion of the wooden sash part 30 and a second generally flexible lip or bead-like portion 44 projecting inwardly from sheath 40 for engagement in sealing relation along marginal portions of the glass panel 10 in final securement. Sheath 40 isalso formed to have conforming surfaces with part 30, particularly in the area of reverse curved portion 31, as to conform to the external configuration of part 30. As illustrated in FIG. 1, the inner face part 30 is provided with a pair of longitudinally extending inset or grooved portions 46 along opposite edges thereof for receiving inwardly extending flanges 48 which form a portion of generally U- shaped sheath 40. Accordingly, when the parts are in disassembly, the first wood part 30 can be inserted lengthwise within sheath 40 with the flanges 48 lying within the inset portions 46 of part 30. It will be appreciated that each sheath 40 and its associated part 30 are coextensive in length and that the ends of sheath 40 and part 30 of the wooden sash are formed at opposite ends to provide mitered joints with adjacent exterior sash members. Part 32 is joined by mortised and tenoned or slotted and pinned as in conventional rectangular wooden window construction.

To form the window unitillustrated in FIGS. 1-7, the spacers 16 are first filled with desiccant 26 and arranged to form a pair of like rectangular frames by inserting the angle members 24 into the open ends of adjoining spacers 16, as best seen in FIG. 2. Spacers 16 are then arranged to lie between the three glass panes 14 of similar rectangular configuration such that the edges of the glass panes and the outer peripheral edges of spacers 16 lie substantially flush, one with the other, as seen inFIG. 3. The panel is preferably supported during assembly by an underlying support in contact with the center of the panel such that the peripheral edges of the panel are fully exposed. The panel is then clamped in assembled relation by a clamp indicated schematically at C in FIG. 3.

A sealant is then applied along the outer edges of the panel by a suitable applicator, indicated at A in FIG. 4, filling the spaces between the peripheral edges of panes l4 and inset portions 22 of spacers 16 as illustrated in FIG. 5. The sealant preferrably comprises a two-part polysulfide compound having a polymer base. This compound has an extremely high adhesive quality and seals the spacers to the peripheral edges of glass panes 14 such that dead air spaces 18 are hermetically sealed. Before the polysulfide compound is set, the parts 32 of the wooden sash frame are assembled one with the other at their corner joints, i.e. mortise and tenon or slotted and pinned construction, to form a rectangular frame with the groove 36 lying open to one side of the frame. The glass panel is then disposed within the groove 36 with the marginal face portion of the underlying glass pane 14 directly butting the inner face portion of groove 36 as best illustrated in FIG. 5. The glass panel 10 and parts 32 are formed such that a space is provided between the periphery of the glass panel and the base of groove 36 for receiving additional sealant 50 provided by a suitable applicator as illustrated in FIG. 5. As also illustrated in FIG. 5, the upper glass pane lies flush with the upper face of part 32.

While the foregoing assembly operations are taking place, wooden sash parts 30 may be inserted endwise within their associated sheaths 40 as previously described. Note that the sheaths 40 are not secured directly to the enclosed part 30 but are retained thereon by flanges 48 and inset portions 46 against movement other than an endwise movement when in disassembled relation. This is a particular feature hereof as it is desirable to obtain, when the window is finally constructed, a circulation of air between sheathing 40 and wood part 30 as well as to permit relative expansion of wooden part 30 and the sheathing to avoid cracking the latter. Note in FIGS. 6 and 6A that the soft flexible plastic head 44 in its natural condition prior to assembly and forming a part of sheath 40, projects inwardly beyond the inner face of part 30.

To secure the parts 30 and 32, respectively, one to the other,thereby clamping the marginal portions of the glass pane 10 within groove 36, a suitable glue or epoxy is provided along the wooden portion of the inner face of the composite woodplastic part for adhering the the inner face of the second part 32. Thus, when the parts 30 and 32 are finally secured one to the other, they form the glazing groove 38 for receiving marginal portions of and retaining the glass pane. Also, by applying the glue or epoxy only to the wooden portions of the part 30 along its inner face, it is seen that the flanges 48 of sheath 40 are not fixed to either of parts 30 and 32, but are free to permit relative movement between sheath 40 and the wooden parts. The sheaths 40, however, cannot be removed as they butt one another in final assembly at the mitered comer joints as indicated in FIG. 7 and are thus retained on the completed window unit.

As illustrated in FIG. 7, the mitered comers of the sheaves 40 are sealed one to the other. This can be accomplished by employing a solvent to soften the material of the sheath such that it can be pressed and welded together. When the solvent evaporates, the joint is effectively sealed. Alternatively, the edge portions of the plastic sheaths may be heat welded, one to the other, by employing a suitable heat welding machine.

It is a significant feature of the present invention that the soft flexible bead 44 formed along the inner edge of sheathing 40 forms a weather seal against the panel 10. To this end, flexible bead 44, in the dual extrusion process, is formed as to project in its natural state inwardly of sheath 40 and part 30 in assembly therewith as indicated in FIGS. 6 and 6A. Accordingly,

. when part 30 is secured to part 32, bead 44 will bear against the face portion of the outer glass pane 14 in sealing relation therewith to preclude moisture or water from entering the glazing groove.

Referring to FIG. 9, the bottom rail of the window sash is preferrably provided with a plurality, preferrably two, of weep holes or slots 52 fro the purpose of carrying away any moisture or water which may get past the bead seal 44. The weep holes or slots 52 are also provided to allow air to circulate around the perimeter of the sash immediately under bead 44. The slots 52 comprise a slot formed along the inner face of part 30 and opening under the inner edge of the upper flange 48 of sheath 40. The slots 52 open through the bottom of the lower rail and are preferably formed after part 30 has been inserted within the sheath 40, the lower edges of the sheath 40, including its lower flange 48, being cut away whereby sheath 40 can receive part 30 and remains free for movement relative to part 30 in final assembly.

Referring now to FIG. 8, there is illustrated a dual pane insulating glass panel disposed within a sash 12a constructed similarly as previously described with respect to sash 12. In this form, the spacers 16a are somewhat wider than the spacers 16 of FIG. 1 and have the same generally T-shaped configuration. In assembling the two-pane panel, the panel is first formed by disposing spacers 16a about the margins of one of the sheets of glass and then disposing the other sheet of glass on top of the spacers. Sealant is applied, as previously described, and the completed panel 10a is disposed within the groove 36a of parts 32a which have been secured one to the other to form a rectangular frame. The sheathing 40a, identical to sheathing 40, receives part 30a, similarly as previously described, and the wooden parts are adhesively secured one to the other. There is thus fomied a window unit having a dual pane insulating glass panel with a protective coating on one side and a glazing bead 44a which forms a seal about the margins of the outer pane of glass. It will of course be appreciated that the protective outer covering can be provided in a single pane window unit wherein the glass pane is glazed within a groove formed in a part corresponding to part 32 or 32a with the other sash part having the protective coating secured thereto similarly as described.

It will be appreciated that the objects of the present invention are fully accomplished by the foregoing construction in that there has been provided an improved window unit having .a protective covering along the portion of the wooden sash exposed to external environmental conditions. Moreover, the foregoing construction provides a flexible seal along the outer pane to preclude the ingress of moisture and/or water to the glazing seal. Furthermore, the foregoing construction provides a window unit having a protective covering along its externally exposed wooden sash portion for use with single, double, or triple pane insulating glass panels as desired.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:

l. A window unit comprising a glass pane, wooden sash members joined one to the other and extending about the periphery of said glass pane, said members having grooves formed along their inner faces for receiving the edge portions of said pane, said sash members being each comprised of first and second parts having exposed wood portions on respective opposite sides of said window unit, means for securing said first and second parts one to the other, said first and second parts having cooperating portions forming said grooves including the rear face of each said first part forming a side wall for the groove associated therewith, each of said second parts being recessed along its inner face to form the base and opposite side wall of the corresponding groove, coverings carried by said sash members about exposed portions of said first parts on one side of said window unit to provide a protective surface therefor, each of said coverings including a generally U-- shaped, unitary, composite extrusion sheath of vinyl plastic material, a first portion of said sheath being semi-rigid and providing the major portion of said covering along said one side face, a second portion of said material being flexible and extending along the inner edge portion of said covering to bear in sealing relation against said pane, sealant means within said grooves bonding said wood sash members to said glass pane about the peripheral edge portions thereof, each of said first parts being recesses formed along the rear face thereof and along its inner and outer edges, said recesses forming with the rear face of said second part a pair of slots extending along the inner and outer edges of each said sash member, the opposed edges of each of said sheaths having inwardly directed flanges disposed within said slots, the flange in the slot along the inner edge of each said sash member overlying a portion of the side wall of said first part.

2. A window unit according to claim 1 including a second glass pane forming a glass panel with said first mentioned pane, means for spacing said panes one from the other including a spacer engaging between the laterally facing peripheral edge portions of said panes, said spacer extending about said peripheral edge portions to define an air space with and between said panes and forming panel edge portions with said glass edge portions, said panel edge portions being received within said grooves, said sealant means bonding said wood sash members to said glass panes and said spacers forming a hermetic seal between said spacers and said peripheral glass edge portions about said air space.

3. A window unit according to claim 1 including second and third glass panes forming a glass panel with said first mentioned glass pane, means for spacing said panes one from the other including a plurality of spacers engaging between laterally facing peripheral edge portions of next adjacent panes of glass, said spacers extending about said peripheral edge portions to define an air space with and between each adjacent pair of panes and forming panel edge portions with said glass edge portions, said panel edge portions being received within said grooves, said sealant means bonding said wood sash members to said glass panes and said spacers forming a hermetic seal between said spacers and said peripheral glass edge portions about said air spaces.

4. A window unit according to claim 1 wherein one of said first and second parts of at least one sash member has a passageway communicating between the outer face of said one sash member and the groove fonned along the inner face of said one sash member.

5. A window unit according to claim 4 wherein said passageway is formed along the rear face of said one part.

6. A window unit according to claim 5 wherein the flange of said sheath extending along the outer face of said one sash member has an opening therethrough in communication with said passageway.

UNITED STA'IES PATEN'! OFFICE C E R 'l I F l C A 'E E 0 l5 C U .Ei R E (I 'l. E U N Patent NO. 3,667,179 Dated June 6, 1972 Morris M. Eisenberg Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In Column 5, line 44, "the the" should read --to the-- In Column 6, line 1, "fro" should read --'for-- In Column 7, line 8, Claim 1, "being" should read --having- I Signed and sealed this 12th day of December 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer v Commissioner of Patents FORM po'wso USCOMM-DC GOHIC-PGQ a US. GOVERNMENT PRINTING OFFICE I969 0-356-3J4 

1. A window unit comprising a glass pane, wooden sash members joined one to the other and extending about the periphery of said glass pane, said members having grooves formed along their inner faces for receiving the edge portions of said pane, said sash members being each comprised of first and second parts having exposed wood portions on respective opposite sides of said window unit, means for securing said first and second parts one to the other, said first and second parts having cooperating portions forming said grooves including the rear face of each said first part forming a side wall for the groove associated therewith, each of said second parts being recessed along its inner face to form the base and opposite side wall of the corresponding groove, coverings carried by said sash members about exposed portions of said first parts on one side of said window unit to provide a protective surface therefor, each of said coverings including a generally U-shaped, unitary, composite extrusion sheath of vinyl plastic material, a first portion of said sheath being semi-rigid and providing the major portion of said covering along said one side face, a second portion of said material being flexible and extending along the inner edge portion of said covering to bear in sealing relation against said pane, sealant means within said grooves bonding said wood sash members to said glass pane about the peripheral edge Portions thereof, each of said first parts being recesses formed along the rear face thereof and along its inner and outer edges, said recesses forming with the rear face of said second part a pair of slots extending along the inner and outer edges of each said sash member, the opposed edges of each of said sheaths having inwardly directed flanges disposed within said slots, the flange in the slot along the inner edge of each said sash member overlying a portion of the side wall of said first part.
 2. A window unit according to claim 1 including a second glass pane forming a glass panel with said first mentioned pane, means for spacing said panes one from the other including a spacer engaging between the laterally facing peripheral edge portions of said panes, said spacer extending about said peripheral edge portions to define an air space with and between said panes and forming panel edge portions with said glass edge portions, said panel edge portions being received within said grooves, said sealant means bonding said wood sash members to said glass panes and said spacers forming a hermetic seal between said spacers and said peripheral glass edge portions about said air space.
 3. A window unit according to claim 1 including second and third glass panes forming a glass panel with said first mentioned glass pane, means for spacing said panes one from the other including a plurality of spacers engaging between laterally facing peripheral edge portions of next adjacent panes of glass, said spacers extending about said peripheral edge portions to define an air space with and between each adjacent pair of panes and forming panel edge portions with said glass edge portions, said panel edge portions being received within said grooves, said sealant means bonding said wood sash members to said glass panes and said spacers forming a hermetic seal between said spacers and said peripheral glass edge portions about said air spaces.
 4. A window unit according to claim 1 wherein one of said first and second parts of at least one sash member has a passageway communicating between the outer face of said one sash member and the groove formed along the inner face of said one sash member.
 5. A window unit according to claim 4 wherein said passageway is formed along the rear face of said one part.
 6. A window unit according to claim 5 wherein the flange of said sheath extending along the outer face of said one sash member has an opening therethrough in communication with said passageway. 